Dendrocalamus elegans

Specimens: BS-0538 [C8-R04] (living plants) = CS-3040, Bu Boi Island, Langu, Satun, southern Thailand (บุโบย อ. ละงู จ. สตูล), wild, received as "Dendrocalamus elegans", 29 May 2010; BS-0538-1 [†] (living plant), same location, received 29 May 2010, died 2013.

Characteristics: Habit open-spaced caespitose. Rhizome pachymorph (long, or with a long neck), distance about 20–35 cm between old and new culm. Culms over 10 m long by 2.5–3.2 cm basal diameter, widely arching to the ground or scandent. Young shoots conical; sheath with an orange tint, thickly covered with white mealy wax in mature plants, usually without hairs; culm-leaf blades deflexed, green; emerge from June to August. Culm-internodes glabrous, smooth, thinly to thickly farinose when young, except on basal culm for up to ca. 0.5 m above the ground, the farina easily removable; (17) 22–30 (36) cm long at the mid-culm, 3.6(!) cm in diameter, solid on the basal culm, solid or nearly so on the mid-culm, very thick-walled on the upper culm. Culm-nodes slightly prominent; sheath scar a prominent corky ring, shiny black when young, dull light brownish when old; aerial roots typically none, but may occasionally develop on the lowest node. Branch-buds solitary, from the basal node up. Branches typically none (or with a single thin short one) on the basal and lower culm, to 1, 2, or 3 equally dominant branches on the lower, mid, and upper culm, each 1/3 to 1/2 as thick as the main culm, elongating to 5 m, the mid-culm and upper culm with few to many additional very slender, subequal, short branches, ca. 0.5–0.8 (1) m long, the branch nodes prominent; branching intravaginal. Culm-leaves early deciduous. Culm-leaf sheath 1/2 as long as the internode or a little shorter, almost glabrous (but with a few blackish hairs when young), light green, with a reddish tint towards apex and margins, thinly to thickly farinose in the upper one-third of 2–3 m tall young shoots, thus appearing bluish-white; margins short dark ciliate; apex truncate. Culm-leaf auricles rim-like, very low, dark, without bristles. Culm-leaf ligule short, dark, finely toothed, and with pale bristles when young. Culm-leaf blade patent, green. Foliage-leaves (5–) 7 (–12) per branchlet. Foliage-leaf sheath short pale hairy when young. Foliage-leaf auricles small, pale bristly, bristles few, 3–5 mm long. Foliage-leaf ligule short, 0.5–1 mm, blackish when young. Foliage-leaf blades small, 5–15 × 0.7–1.7 cm, rarely somewhat larger, to 22 cm long, to 2.9 cm wide, linear-lanceolate, densely velvety-hairy beneath (lasting when old), glabrous above; base rounded to wedge-shaped; margins antrorsely scabrous; apex long acuminate to attenuate; pseudopetiole 1.0–1.5 mm short.

Comments:

(1) This bamboo was recorded by the collector to be very small-statured and limestone-tolerant, but the ultimate clump height or culm length on-site was not recorded. By its 4th year in cultivation (in soil of neutral pH), culms had exceeded a length of 10 meters.

(2) Living plants set in the ground turned out to be somewhat delicate, and some plants died for unknown reasons (perhaps due to too low a pH).

(3) The culms have no longevity and may die after only a few years, but they are strong and not quickly rotting (dead basal culms 1.3 cm thin were still difficult to cut with pruning shears after two years).

(4) All plants have remained in the vegetative state; there are no signs of incipient flowering (observed Aug. 2013 – Aug. 2023).

Specimen: BS-0168 [C4-R02] (living plants), southern Thailand, without precise location, wild, received by ธ. ล. in 2010.

Characteristics: Habit tight caespitose. Rhizome pachymorph, short, distance about 6 cm between old and new culm. Culms widely arching, scandent, over 6 m long. Young shoots conical; sheath green, dark hairy, not farinose; culm-leaf blades spreading; emerge from April to August. Culm-internodes glabrous, smooth, dark green, initially somewhat farinose or without farina, 32–42 cm long, 1–1.7 cm in diameter, thick-walled, basally solid, or nearly so (culm of 1.2 cm in diameter with lacuna 3 mm at ca. 60 cm culm height above the ground). Culm-nodes slightly prominent; sheath scar a prominent corky ring, shiny black when young and with fuzzy deciduous brownish hairs, dull light brownish when old. Branch-buds solitary, broadly ovate to subrotund, from the basal nodes up. Branches on the lower culm typically none (up to about 3 m), 1 branch from the mid-culm up, 1/2 to 2/3 as thick as the main culm, elongating, the upper culm with several thin shorter branches, branch nodes slightly prominent; branching intravaginal. Culm-leaves deciduous. Culm-leaf sheath less than 1/2 as long as the internode, green when young, intensely covered with appressed blackish rigid hairs, straw-colored when dry, not farinose; margins eciliate; apex horizontally truncate, junction with the blade about 1/3 the width of the apex. Culm-leaf auricles rim-like, very low, inconspicuous, glabrous, adnate to the blade base margins and extending along the sheath apex to the sheath margins, oval-rounded at the ends and minutely protruding, without bristles, or with a few to ten 5–10 mm long pale bristles at each of the rounded ends. Culm-leaf ligule rather low, 0.5–1 mm high, margin finely toothed, not bristly, or rarely with a few very short pale bristles. Culm-leaf blade patent to reflexed, green when young. Foliage-leaves 5–8 per branchlet. Foliage-leaf sheath glabrous. Foliage-leaf auricles small, inconspicuous, with a few long pale bristles when young. Foliage-leaf ligule short, inconspicuous, entire, glabrous; the outer ligule a slight glabrous ridge. Foliage-leaf blades soft, 6–14 × 1.2–2.4 cm, with a very fine, short (shorter adaxially) and dense pale pubescence on both surfaces when young (appearing glabrous with the naked eye or touch), becoming glabrous with age, linear to linear-lanceolate; base rounded to wedge-shaped; margins antrorsely scabrous; apex long acuminate; midrib proximally minutely prominent, light green; pseudopetiole short, 0.5–1 mm.

Comments:

(1) It is noteworthy that the auricles of the culm-leaves can develop either with or without bristles.

(2) This bamboo has developed slowly in cultivation but grows well on normal (pH-neutral) garden soil. The plant does not seem to have reached its ultimate size after more than 10 years.